How do I transfer library of pictures from iPhoto to Photo?

For me, the launch of Photos is different (just launch however). Always shown in the menu on the left is item "iPhoto Events". Clicking this item reveals all photos from iPhoto as if already part of Photos. So, it seems that iPhoto and Photos are both part of the same program. I had anticipated that there would be a "process" where photos would be transferred into the new "Photos" program. Thanks for the guidance.